Base structure for electron ray tubes



Oct. 3, 1939. E, RUSKA 2',174,759

BASE STRUCTURE FOR ELECTRON RAY TUBES Filed May 20, 1936 Patented Oct. 3, 1939 UNITED STATES BASE STRUCTURE FOR ELECTRON RAY Ernst Ruska, Berlin-L'ehlendorf, Germany, as-

signor to the firm of Fernseh Akticngesellschaft, Zehlcndorf, near Berlin, Germany Application May 20,

1936, Serial No. 80,888

In Germany May 2'7, 1935 3 Claims.

The present invention relates to base structures for electron ray tubes in which essential parts of the electrode system are associated with the base of the tube.

The electrode systems of electron ray tubes are generally so mounted that the individual electrodes (i. e. rotationally symmetrical electronoptical devices or deflecting plates or deflecting coils) are strung upon a centered system con sisting usually of insulating tubes or rods and fastened in their respective cooperating positions in various ways. The necessarily accurate coaxial positioning of the parts with respect to each other in this case is accomplished by the centering system used in the base of the tube. Such electrode mounting requires great accuracy in fabricating the centering foot.

The second type of construction consists in building up the system independent of the base and connecting the. thus accurately and preliminarily erected structure as a unit with the base of the tube. The junction of the unit system with the base need merely be formed within such limits of accuracy as suffices to permit directing the electrode system accurately as a whole into its correct position with respect to the axis of the electron ray tube. The degree of accuracy hitherto required for producing the base may be decreased since on it depends only, for example, the position of the television image at the bottom of the screen, and which position can readily be adjusted by suitable circuit means.

The present invention relates to the construction of tubes of this type. The tube base consists of two concentric tubes which are fused (blown) together. The lead-in conductors and the wires leading to the system may be located at the junction point of the two tubes or in the wall of the outer tube. The base, after the system is in placewith the said fusion junction directed towards the screen of the tube--may be inserted into the neck of the bulb and fused toether with the outer tube of the base.

The fastening of the system to the tube base is effected in accordance with the present in vention, in such a manner that the connecting member between the base and the electrode system constitutes a funnel or cap portion (hollow cones) made of conducting or non-conducting material and which on the one hand is fastened coaxially at the fusion junction of both base tubes and on the other hand to the electrode system or other part of the base plate forming the cone. The base plate or the hollow cone may simultaneously constitute an electrode, e. g. the anode of the system.

Referring to the drawing:

Fig. 1 shows the hollow cone reposing on the fitting surface of the outer base tube.

Fig. 2 shows the hollow cone according to Fig.

1, as a plan View.

Fig. 3 shows the hollow cone resting on the fitting surface of the inner base tube.

Fig. 4 shows the hollow cone according to Fig. 10 3 as a plan view.

Fig. 5 shows retaining lugs used instead of hollow cone.

Fig. 6 shows a combined arrangement using hollow cone and retaining lugs. Fig. 7 shows the carbon mold with the blown tube base, in section.

The attachment of the hollow cone I to the base in accordance with the invention, may, for example, be effected by extending the cone into n) the inner tube 2 or making it surround the outer tube 3 of the tube base or so that it does both at the same time. The member involved may, for example, be attached at three points separated at angles of 120 as by means of wire eyelets 5 hung on three corresponding hooks or lugs 4 on the outer periphery of the inner base tube or on the inner periphery of the inner tube.

To these wire eyelets a Washer 6 may for example, be hung, and which is threaded upon a 30 screw 7. This screw passes through a disk 8 which likewise belongs to the electrode system and forms a part of the hollow cone at the side turned towards the screen of the tube. Since the hole in this disk is threaded, a correct positioning of the hollow cone and the system with respect to the tube base can always be secured. The wire eyelets, on the other hand, may also be passed direct through a hole in the screwbolts. In this case, however, the hole in the disk upon which the hollow cone rests should have no threads. .The exact position of the hollow cone is secured by screwing a nut on the screw bolts so that the hollow cone is forced against the fitting surfaces of the tube base.

The wall which forms the hollow cone, notwithstanding if the cone extends into the inner tube or surrounds the outer, may be preferably provided with recesses so that only a few holding lugs 9 remain which are then forced against the wall of the outer or inner base tube. These lugs may for example be replaced by angle pieces. The lugs or angle pieces are so disposed that they are displaced 120 or 90 with respect to each other. Naturally a larger number of lugs or angle pieces may be chosen so that for example a retaining crown is formed. If the lugs or angle pieces are intended to bear against the inner side of the inner tube and on the outer side of the outer tube of the tube base, it is preferable so to dispose the lugs or the angle pieces that the lugs which lie on the inner side are opposite the recesses formed by the outer lugs.

The retaining means according to the invention may also be so arranged that the hollow cone bears against the inner side of the inner tube, lugs or angle pieces being provided for the outer side of the outer tube, or conversely.

Holes H1 may be provided in the base plate upon which the cone is fastened, or else on the cone itself and through Which holes the lead-in conductors pass freely. The holes are then preferably chosen so large that an exact positioning of the lead-in conductors need not be required. In order to attain a rigid and sufficiently accurate coaxial seat for the hollow cone (which for example may be of metal) on the glass base, the base should be blown in a carbon mold H. In order to mark the places where the lead-in conductors subsequently occur, the bottom of the mold may be provided with holes I2 at these points, into which, during the blowing procedure, small bumps are extruded. The carbon mold insures maintaining the position of the inner tube coaxial with the cone.

The system is associated with the retaining members by means of screws, rivets, or welding, or by suitably bending retaining lugs in place. The parts of the system may be disposed on both sides of the cone and centrically therewith and hence may also be centrically arranged with respect to each other.

This method of fastening the electrode system to the base of the tube may naturally also be applied to electron ray tubes which in lieu of a foot consisting of two tubes use a pressed foot or a single tube for holding the lead-in conductors.

I claim:

1. In combination with a Braun tube having a cylindrical stem, an annular double walled reentrant stem formed integrally therewith, an electrode supporting element shaped to engage one wall of said annular stem tightly, lugs peripherally disposed on the other wall of said reentrant stem, and means for linking said electrode supporting element to said lugs.

2. In combination with a Braun tube having a cyindrical stem, an annular double walled reentrant stem formed integrally therewith, an electrode supporting element so positioned and arranged as to engage said annular reentrant stem on its interior and exterior annular surfaces, and lugs disposed about said stem whereby said supporting element may be held.

3 In combination with a cathode ray tube having a reentrantly terminated glass cylindrical stem, an annular electrode supporting base comprising a concentric glass tube positioned Within said reentrant stem and terminally fused therewith, and an electrode supporting member positioned within said tube to engage the outer cylindrical surface of said reentrant portion of said stem and the inner surface of said concentrically disposed tube.

ERNST RUSKA. 

